A FORENSIC APPROACH TO SOLVE A GROUND WATER CONTAMINATION PROBLEM

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1 A FORENSIC APPROACH TO SOLVE A GROUND WATER CONTAMINATION PROBLEM Coby A. Scher and Dennis L. Caputo Quest Consulting, Inc West Loop South, Suite 310 Bellaire, Texas ABSTRACT In 2000, a subdivision outside a small city in southeast Texas discovered that the water supply wells that individual households had drilled were contaminated with trichloroethylene or TCE as it is commonly called. Since the extent of TCE contamination seemed to extend for over a mile in length, it was thought the event or events leading to the contamination had occurred some years ago. The shape of the plume seemed to indicate that the source of the TCE contamination originated at a closed industrial facility located approximately 600 yards north of the subdivision. However, the width and shape of the plume implied that there might have been more than one source or that ground water flow had shifted direction in the past. Finally, one particular well serving a small commercial facility located at the western edge of the plume seemed to have the highest concentration of TCE. While the closed industrial plant was already subject to a state-led voluntary cleanup, the subdivision residents and nearby facilities whose wells had been impacted joined forces and sued the closed plant s owners for damages. The closed plant s owners, while not admitting any liability, agreed to install temporary carbon adsorbers on each contaminated well while the field investigation to determine the plume s parameters proceeded under state guidance and oversite. Since the timing of the field investigation and the lawsuit did not precisely coincide, it was necessary to accumulate data to support the plaintiff s lawsuit while at the same time refute the defendant s attempt to deflect responsibility for the TCE contamination. Superimposed on this scenario was the constraint to not independently conduct a field investigation to support the plaintiff s allegation. Thus, it was important to analyze the existing and evolving data to support the case, ensure that the conclusions reached were scientifically supportable, and refute the defendant s attempts to blame someone else for most if not all of the ground water TCE contamination. The result was that forensic methodology, which is the application of the art and science of engineering in matters that will or may ultimately appear in court, was used to characterize the history, source, movement, and present disposition of the TCE ground water plume. KEYWORDS Forensic, trichloroethylene, TCE, ground water, lawsuit, hydrogeology, Phase II, liability, isotopic ratio, research.

2 INTRODUCTION To design and complete an effective environmental forensic investigation, the environmental professional must know: 1. Historic and current operations on the subject site 2. Historic and current operations on surrounding sites that could impact the subject site 3. Raw materials, intermediate products, by products, final products and wastes from historic and current operations 4. Chemical and physical characteristics of each of these materials 5. Environmental transport and fate for each of the these materials 6. Site geologic, hydraulic and/or hydrogeologic conditions at and surrounding the site While the goals of a typical Phase II investigation may be met by determining the presence of hazardous substances or petroleum products, the environmental professional when conducting an environmental forensic investigation will often need to determine the chemical form of each of the substances and the process that created each of them. For example, a typical Phase II goal may be achieved by confirming the presence of lead in the soil or groundwater above a certain standard. On the other hand, to achieve the goals of an environmental forensic investigation, the environmental professional may need to determine the specific lead compounds present and ratios of those compounds, to identify possible sources of the lead found at the site. The ratio of lead to other elements or compounds may also be needed to identify possible sources. These ratios can aid in determining if the lead came from combustion sources, wastewater treatment residues, or lead acid batteries. Thus it can be seen that one type of professional background or education may not provide one all of the tools needed to perform a thorough forensic environmental investigation. Frequently, a team of individuals including chemists, chemical engineers, atmospheric scientists, hydrogeologists, and other disciplines band together to execute the work. However, the best training and background is chemical engineering because knowledge of chemical processing and manufacturing is gained through schooling and experience. Only with an innate historical knowledge of how chemicals are manufactured, what raw materials are used, how chemicals react and are transported, how residuals are managed, and what a mass balance calculation tells one can you pursue an inductive analysis of a complex environmental scenario. Now with the Internet available as an almost limitless information source, the research required to analyze chemical information, processes, and reactions can be easily accessed. While each chemical contamination situation is unique, careful consideration of what actually transpired will lead one to the answer. OVERVIEW In the spring of 2001, residents of a suburb of El Campo, Texas were told that there was TCE contamination in water wells serving their residences. In addition, several nearby businesses not

3 on city water also discovered TCE contamination in their wells. A nearby closed aluminum extrusion plant owned by Alcoa (that also happened to be roughly up-gradient) was suspected as the source of the TCE and initially took responsibility for surveying and testing all of the private water wells in the area. Also, because the plant was already in the Texas Voluntary Cleanup Program (VCP) for other reasons, the Texas Commission of Environmental Quality ordered the plant to install ground water monitor wells to define the horizontal and vertical extent of contamination. At the same time, the plant agreed to temporarily install and maintain carbon filters on the affected wells to capture TCE and any daughter products. City water was nearby, but since the affected wells were outside the city, no entity wanted to bring in water because of the cost and logistics. Also, at about the same time, the owners of the affected wells banded together and sued the presumed source of the TCE, the owners of the closed extrusion plant. Quest was hired by one of the plaintiff s attorneys to provide expert technical testimony in the suit. A constraint though was to not perform any independent testing but to rely upon the defendant s data for forming any technical opinions. The defendant s VCP field investigation did not proceed as swiftly as the case unfolded and even then, the defendant was slow to release any substantial results for fear of implicating themselves. Quest, therefore, had to rely almost completely upon historical information, state initiated investigations, depositions, and investigations performed by several of the businesses. Fortunately for Quest, several basic data sources presented themselves. The historical records and depositions showed that TCE was used and disposed of for some period of years at the plant. Various Phase I Assessments (because the plant had been bought and sold several times since 1990) and limited Phase II investigations demonstrated that some TCE was present at or near the plant. However, the shape of the plume and TCE water well concentrations were inconsistent with the one point source theory and suggested either several sources of TCE or a series of events that would have defined the plume s present shape and TCE distribution. Recognizing that the plume had over 30 years to evolve into its present shape, it was important in winning the lawsuit to recreate the sequence of events leading to the plume s present form. Fortunately for the plaintiffs, the lawsuit discovery process revealed some key s among the defendant and its consultants pointing to how they intended to shed responsibility. In fact, using some fairly obscure but, in theory some technically valid analysis, they intended to show that there were indeed three plumes, not one, and that the plant (defendant) was only responsible for one of them. It was incumbent upon Quest to refute these arguments and show that the extrusion plant was the sole source of TCE and that simple hydraulic transport could explain the shape and TCE concentrations in the plume. METHODOLOGY The primary complaint by the citizens was that the defendants had contaminated their drinking water wells with trichloroethylene (TCE), a solvent that had reportedly been used at the plant in the 1960s and 1970s. The wells used by the citizens were all located down gradient roughly ½ to 1 ½ miles from the plant and was their only source of potable water. The aluminum extrusion plant was not the only industry located in the general area, but appeared initially to have the potential to be the largest TCE user based upon historical purchase records and recollections of the plant personnel deposed. No other plant was named in the lawsuit.

4 The aluminum extrusion plant, under the ownership of Reynolds Metals Company in the 1990s, was already involved in remediation with the Texas Commission on Environmental Quality (TCEQ) because of heavy metal contamination discovered in the soil at the facility. As a consequence of being accepted in the Voluntary Compliance Program (VCP) with TCEQ, Reynolds was required to monitor for metals and other constituents in the groundwater at the site within the plant boundaries. It was during this period of groundwater monitoring in the period that TCE was discovered in the groundwater onsite. TCE was eventually found by Reynolds (and after the purchase by Alcoa) to be located in the soil regime adjacent to and under the extrusion building and down gradient at the property line. Alcoa was required to drill monitoring wells offsite and test for TCE. Eventually, the testing of monitoring wells and citizen drinking wells revealed a TCE plume as shown in Figure 1. The outline of the plume exhibits TCE concentrations above the EPA and TCEQ Maximum Concentration Limit (MCL) for TCE of 5 ug/l (~5 ppb) in potable water. Alcoa was astute enough to add carbon canisters to the individual wells at their expense to remove TCE from the water. Simultaneously, the TCEQ added the groundwater contamination issue to the Alcoa VCP meaning that a state-mandated process of groundwater evaluation and remediation would begin. It was about this time that the citizens sued the defendants for diminution of property value and various medical problems. The case at this point seemed rather straight forward since no other plants or defendants were named. Alcoa decided to fight the lawsuit, probably realizing that the TCE groundwater plume would either be (1)cleaned up by them or (2)the private citizens put on a public water and sewer collection and treatment system,. The cost of either alternative would be in the tens of millions of dollars including all capital costs and 30+ years of operating costs. Alcoa decided to contest the lawsuit and only accept some of the blame for contaminating the groundwater. Their strategy was to try to establish a situation where Other industries would be named because they used TCE, Midnight dumping of TCE may have occurred, There were three (3) independent groundwater plumes and they only contributed to one of them, and If enough obscure science is thrown at the case, some of it might stick and create doubt in the minds of TCEQ that they were the only polluter. This is when the forensic environmental investigation and analysis became important. A standard environmental assessment of the situation as described above (and which was performed) would indicate that Alcoa and its predecessors were indeed the only user and contributor of TCE to the groundwater. The process would not provide the answers to describe the unusual shape of the plume (Figure 1) nor the subtleties that Alcoa created during the development of the case. One of the key components of forensic analysis is to review all pertinent depositions, manuals, standard, literature, design drawings, and specifications. To explain the TCE distribution, it was important that Quest consider any and all possibilities of sources, hydraulics, materials transport, and chemistry. The result was that an array of possibilities had to be considered in order to deduce what actually happened. From analyzing this realm of potentials, plus working through considering and refuting the defendants high-

5 tech methodology, plus utilizing some data obtained by a parallel group of plaintiff s consultants, plus utilizing the defendants own slowly evolving data and the TCEQ s reaction to its conclusions, the actual mechanism for TCE source(s) and transport was explained. It turned out that all of the TCE actually emanated from the extrusion plant, but a line source of a leaky sewer line leading away from the plant became a significant secondary source and a highcapacity industrial pumping well distorted the plume s shape and TCE concentration enough to imply a second source. Some experienced engineering and hydrogeology was needed to explain the sequence of events that led to the plume s shape and TCE distribution. As orientation, Figure 2 shows the location of the El Campo Aluminum Company site and the surrounding industries. The citizens lived in the Westhill and Quail Meadows subdivisions and beyond the El Campo city limits. North of Highway 59, houses were on city water and any wells had been closed years before. None of these citizens were party to the lawsuit. Alcoa s attempt to decrease its liability centered on the following arguments. Because Alcoa was already in the TCEQ VCP program and liable for the total cleanup bill, it was to their economic advantage to make any or all of the following arguments stick with the TCEQ. Only in that manner could Alcoa reduce both its VCP costs and its financial exposure in the lawsuit. Demonstrate through soil analysis of surrounding industries that they could have used TCE. Pin the plume to the east on midnight dumping. Show through some regional geology considerations that the groundwater flow could not create the plume shape just from their plant. Show that other TCE sources such as historical pesticide spraying, treatment of septic systems, other household uses, etc. could account for the plume shape. Use non-traditional environmental chemistry such as isotope ratios, inorganic species ratios, TCE degradation products, etc. to explain the plume shape and TCE distribution. Use a box plot statistical method to account for the data distribution. The environmental forensic investigation was divided into two major thrusts; geological/hydro geological and historical/chemical. Since legal discovery had revealed from Alcoa s s their overall and even some details of their strategy, an effort to counter their eventual claims was begun by the plaintiffs. After Alcoa submitted their claims to the TCEQ in November 2003 and by copy to the plaintiffs, the TCEQ independently performed their own analysis which resulted in the same technical conclusions reached by the plaintiffs and their experts. The conclusions reached by the plaintiff s experts and the TCEQ were the following: The source of TCE at the El Campo facility would contaminate the underlying groundwater, which would flow to the southwest. The variable nature of the aquifer materials and hydraulic conductivity would cause dispersion of the TCE. Dispersion leads to lateral spreading of a contaminant and causes a contaminant

6 boundary to extend laterally and down gradient beyond the center of mass of the contaminant. It is also evident from the distribution of TCE, aquifer thickness, transmissivity, and hydraulic gradient that the entire areal extent of TCE contamination is unlikely to have been caused only be a single source located at the plant. Rather, the data indicate that, in addition to a source at the facility, there was also a line source of TCE that extended parallel to Lily Street along the southern margin of the El Campo facility to some distance east of Palacios Street. It is likely that the line source was a ditch or sanitary sewer that had served as a receptor of TCE some time in the past 1. (See Figure 3). Indeed, subsequent borings along the line source found substantial concentrations of TCE in the soil. No other sources of TCE contamination have been located in the vicinity of the Property, despite efforts to do so. The TCE found in the southern portion of the plume may have a slightly different isotopic carbon/chlorine than the remainder of the plume (south of US 59), but the referenced data is only for recently manufactured TCE (1990 and later) and does not address the following variables 5 : 1. The supplier of TCE to the aluminum plant likely received their TCE from a variety of manufacturers during the years of TCE release from the plant because it purchased TCE from Van Waters and Rogers, a chemical wholesale supplier. The result is a mixture of carbon/chlorine isotopic ratios in the contaminated groundwater. 2. TCE manufactured by the chemical companies vary in isotopic carbon constituency depending upon the source of the ethylene; i.e., whether the ethylene was cracked from gas, distillate, or heavy oil. Ethylene is the hydrocarbon molecule that is the primary building block for TCE. 3. Chlorine in TCE exhibits a much more uniform isotopic ratio from manufacturer to manufacturer because almost all of the chlorine made in this country is a co-product (along with caustic) of the electrolysis of seawater. The small range is probably due to variation in the diffusion process used in chlorine manufacture and purification. 4. If a slightly different δ 13 C ratio interval is chosen to construct the plume map, the plume will be uniform throughout. This interval corresponds much closer to the actual ratios of the manufactured TCE as of the early 1990s. However, it does not address the ratios of isotopic carbon that occurred from the various TCE manufacturers in the 1960s and 1970s for which there is no data. One would also expect a stronger influence of a lower negative δc 13 upon the southwest section of the plume because either it contains more TCE from a particular source or the age of the plume varies somewhat internally. That would happen if the TCE releases caused by different isotopic ratios occurred at different times during the use of TCE at the plant. This would be true either since the TCE water well data indicates that there was a TCE release to the east or southeast from a line source in the easterly direction from the plant along Lily Street (see Figures 1 and 3). The chemical data for inorganic species (boron, chromium, chloride, etc.) is consistent with what one would expect near a source of inorganic discharges.

7 Since the quantity of these discharges from ditches, piping leaks, ponds, etc at the Property were small in comparison with the groundwater flow, the effect would be minimal, and the species concentration would be localized. The exchange capacity of the upper feet of the clay-type property soil matrix would also minimize any far-reaching impact by providing both cation and anion soil sites to complex or exchange any inorganic species 2. The organic data in the plume indicate that very little degradation of TCE has occurred in the TCE plume. TCE degrades most rapidly in anaerobic reducing conditions (lack of oxygen). The absence of degradation products implies that the aquifer is oxidizing and contains oxygen. The implication is that natural biological attenuation will probably not work to degrade unless a co-metabolite or oxygen scavenger or both are injected into the TCE plume. Even under these conditions, MCL levels may be difficult to reach 2. Research into historical uses of TCE by surrounding industries, aerial spraying, or homeowner use revealed no other sources that could account for the TCE plume distribution and concentration 5. Box plots do not portray an objective statistical analysis of the data and can be used to portray data in a variety of subjective manners 3. To conclude the case, the use of an environmental forensic approach enabled the plaintiffs to win the case with a substantial financial settlement from Alcoa and its predecessors. Lessons Learned The technical issues involved in this lawsuit and the methodology used to determine what really happened provide real insight into the use of forensic science and engineering. The following highlights are important to providing an accurate and winning strategy: 1. Express an opinion only when it is founded on adequate knowledge. This means that a detailed investigation and study must be made. 2. Inspect the site and evidence personally whenever possible and witness all tests where practical. Understand the test results and their limitations. Make sure that you are privy to current events, field tests, reports, etc. in ongoing activities related to the litigation. 3. Make thorough and detailed inspections, taking color photographs and personally collecting other data to provide documentation and study material. 4. Review all pertinent discovery material, depositions, manuals, standards, reports, literature, design drawings, and specifications. 5. Recommend to your client the need for, and make, all calculations, analyses, and tests necessary to establish and confirm an opinion. 6. Strongly recommend that you and the attorney involved conduct a case status at key intervals and that you conduct a thorough review and analysis of testimony prior to the trial. Make sure that you are current with external issues and activities that may influence the case development. 7. Be prepared for anything you never know what might happen.

8 REFERENCES 1. Preliminary Report Hydrogeology in the Vicinity of the Alcoa-Reynolds El Campo Site, El Campo, Texas, Wayne A. Pettyjohn, February Professional Opinion, Coby A Scher, PE, DEE, February 6, Interoffice Memorandum, Review of Groundwater Characterization Report: El Campo Aluminum Company Site (Alcoa); VCP No. 538, Texas Commission on Environmental Quality, February 10, 2004.

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